1. Field of the Invention
This invention relates to a ball joint (automobile stabilizer, for connecting a stabilizer rotatably installed on the automobile body, to a suspension arm).
The purpose of an automobile stabilizer is to increase the stability of the automobile by creating a resistant force for counteracting a rolling motion of an automobile body such as during sharp turning of the automobile. The stabilizer has a U-shape torsion bar spring installed between a suspension arm and the automobile body to compensate for vertical vibration. Generally, the center part of the U-shaped bar is used as the torsion bar spring and is rotatably connected to the automobile body via a rubber cushion or rubber bush. Each end of the U-shaped bar is connected to a suspension arm through the ball joint.
2. Description of the Related Art
As shown in FIG. 8, a synthetic resin housing 1 of the ball joint used for various automobile linkages in the present technology has an opening 1a at the top and a concave spherical surface 1b extending from the opening 1a, which is designed to serve as a seat. The ball head 2a of the ball stud 2 is secured therein. U.S. Pat No. 3,409,318 and U.S. Pat. No. 4,388,012 are examples of this type of ball joint. A dust seal 3 is also shown in FIG. 8.
In such a ball joint, the concave spherical surface 1b of the housing 1 is designed to be a supporting surface for the ball head 2a of the ball stud 2, and the ball head 2a of the ball stud 2 is to be pressed onto the concave spherical surface 1b through the opening 1a of the housing 1. For this reason, the diameter of the opening 1a of the housing cannot be much smaller than the diameter of ball head 2a. Consequently, the strength for preventing ball stud 2 from being pulled out is low.